Abstract

The use of Salvinia minima Baker for the removal of lead (Pb) and arsenic (As) from aqueous solutions was investigated. In a first approach, the effect of different concentrations of AsO43- and Pb(II) on the growth and accumulation of these metals was studied. The plants tolerated concentrations of 20-40 muM Pb(II) and 200 muM of AsO43-. Toxic effects occurred when 20 muM of Pb(II) and 100 muM AsO43- were used. These effects included growth inhibition (decreased yield of biomass and frond area) as well as an altered frond (leaf-like structure in ferns) appearance and tissue consistence. S. minima showed a high uptake of Pb (34 mg/g dry weight) compared to As (0.5 mg/g dry weight). The uptake of As was inhibited by phosphate. Additional kinetic studies revealed a two-stage accumulation of both elements: a rapid first phase within the first 6-12 hours and a slow second phase up to the end of the 96-hour experiment.